Update to create as well as consume Atom feeds

README.md

@@ -3,21 +3,28 @@
 [![Build Status](https://travis-ci.org/witochandra/webfeed.svg?branch=master)](https://travis-ci.org/witochandra/webfeed)
 [![Pub](https://img.shields.io/pub/v/webfeed.svg)](https://pub.dartlang.org/packages/webfeed)
 
-A dart package for parsing RSS and Atom feed.
+A dart package for parsing and generating RSS and Atom feeds.
 
 ### Features
 
-- [x] RSS
-- [x] Atom
-- [x] Namespaces
-    - [x] Media RSS
-    - [x] Dublin Core
+- [x] Parsing
+    - [x] RSS
+    - [x] Atom
+    - [x] Namespaces
+        - [x] Media RSS
+        - [x] Dublin Core
+- [ ] Generating
+    - [ ] RSS
+    - [x] Atom
+    - [ ] Namespaces
+        - [ ] Media RSS
+        - [ ] Dublin Core
 
 ### Installing
 
 Add this line into your `pubspec.yaml`
 ```
-webfeed: ^0.4.2
+webfeed: ^0.5.0
 ```
 
 Import the package into your dart code using:
@@ -27,10 +34,16 @@ import 'package:webfeed/webfeed.dart';
 
 ### Example
 
-To parse string into `RssFeed` object use:
+To parse string into an object use:
+```dart
+var rssFeed = RssFeed.parse(xmlString); // for parsing RSS feed
+var atomFeed = AtomFeed.parse(xmlString); // for parsing Atom feed
 ```
-var rssFeed = new RssFeed.parse(xmlString); // for parsing RSS feed
-var atomFeed = new AtomFeed.parse(xmlString); // for parsing Atom feed
+
+To generate string from an object use:
+```dart
+var atomFeed = AtomFeed(id: Uri.parse('urn:42'), title: 'a title', ...); // for creating Atom feed
+var xmlString = atomFeed.toXml().toXmlString(); // for creating XML string for Atom feed
 ```
 
 ### Preview
@@ -105,6 +118,10 @@ item.rights
 item.media
 ```
 
+## Contributors
+- Wito Chandra <[email protected]> (author)
+- Chris Sells <[email protected]> (provided XML generation from Atom OM)
+
 ## License
 
 WebFeed is licensed under the MIT License - see the [LICENSE.md](LICENSE.md) file for details

analysis_options.yaml

@@ -1,7 +1,4 @@
 analyzer:
-  language:
-    enablePreviewDart2: true
-  strong-mode: true
   errors:
     unused_import: error
     unused_local_variable: error

example/main.dart

@@ -1,24 +1,16 @@
 import 'package:http/http.dart' as http;
 import 'package:webfeed/webfeed.dart';
 
-void main() {
-  var client = new http.Client();
+void main() async {
+  var client = http.Client();
 
   // RSS feed
-  client.get("https://developer.apple.com/news/releases/rss/releases.rss").then((response) {
-    return response.body;
-  }).then((bodyString) {
-    var channel = new RssFeed.parse(bodyString);
-    print(channel);
-    return channel;
-  });
+  var rssresp = await client.get("https://developer.apple.com/news/releases/rss/releases.rss");
+  var channel = RssFeed.parse(rssresp.body);
+  print(channel);
 
   // Atom feed
-  client.get("https://www.theverge.com/rss/index.xml").then((response) {
-    return response.body;
-  }).then((bodyString) {
-    var feed = new AtomFeed.parse(bodyString);
-    print(feed);
-    return feed;
-  });
+  var atomresp = await client.get("https://www.theverge.com/rss/index.xml");
+  var feed = AtomFeed.parse(atomresp.body);
+  print(feed.toXml().toXmlString(pretty: true, indent: '  '));
 }

lib/domain/atom_category.dart

@@ -5,12 +5,23 @@ class AtomCategory {
   final String scheme;
   final String label;
 
-  AtomCategory(this.term, this.scheme, this.label);
+  AtomCategory({
+    this.term,
+    this.scheme,
+    this.label,
+  });
 
-  factory AtomCategory.parse(XmlElement element) {
-    var term = element.getAttribute("term");
-    var scheme = element.getAttribute("scheme");
-    var label = element.getAttribute("label");
-    return AtomCategory(term, scheme, label);
+  factory AtomCategory.parse(XmlElement element) => AtomCategory(
+        term: element.getAttribute("term"),
+        scheme: element.getAttribute("scheme"),
+        label: element.getAttribute("label"),
+      );
+
+  void build(XmlBuilder b) {
+    b.element('category', nest: () {
+      if (term != null) b.attribute('term', term);
+      if (scheme != null) b.attribute('scheme', scheme);
+      if (label != null) b.attribute('label', label);
+    });
   }
 }

lib/domain/atom_content.dart

@@ -0,0 +1,24 @@
+import 'package:xml/xml.dart';
+
+class AtomContent {
+  String type;
+  String text;
+
+  AtomContent({
+    this.type,
+    this.text,
+  });
+
+  factory AtomContent.parse(XmlElement element) {
+    if (element == null) return null;
+    return AtomContent(
+      type: element.getAttribute('type'),
+      text: element.text,
+    );
+  }
+
+  void build(XmlBuilder b, String kind) => b.element(kind, nest: () {
+        if (type != null) b.attribute('type', type);
+        if (text != null) b.text(text);
+      });
+}

lib/domain/atom_feed.dart

@@ -7,25 +7,24 @@ import 'package:webfeed/util/helpers.dart';
 import 'package:xml/xml.dart';
 
 class AtomFeed {
-  final String id;
+  final Uri id;
   final String title;
-  final String updated;
+  final DateTime updated;
   final List<AtomItem> items;
-
   final List<AtomLink> links;
   final List<AtomPerson> authors;
   final List<AtomPerson> contributors;
   final List<AtomCategory> categories;
   final AtomGenerator generator;
-  final String icon;
-  final String logo;
+  final Uri icon;
+  final Uri logo;
   final String rights;
   final String subtitle;
 
   AtomFeed({
     this.id,
     this.title,
-    this.updated,
+    updated,
     this.items,
     this.links,
     this.authors,
@@ -36,42 +35,61 @@ class AtomFeed {
     this.logo,
     this.rights,
     this.subtitle,
-  });
+  }) : this.updated = updated ?? DateTime.now(); // default value
 
   factory AtomFeed.parse(String xmlString) {
-    var document = parse(xmlString);
     XmlElement feedElement;
+
     try {
+      var document = parse(xmlString);
       feedElement = document.findElements("feed").first;
     } on StateError {
-      throw new ArgumentError("feed not found");
+      throw ArgumentError("feed not found");
     }
 
     return AtomFeed(
-      id: findElementOrNull(feedElement, "id")?.text,
-      title: findElementOrNull(feedElement, "title")?.text,
-      updated: findElementOrNull(feedElement, "updated")?.text,
-      items: feedElement.findElements("entry").map((element) {
-        return AtomItem.parse(element);
-      }).toList(),
-      links: feedElement.findElements("link").map((element) {
-        return AtomLink.parse(element);
-      }).toList(),
-      authors: feedElement.findElements("author").map((element) {
-        return AtomPerson.parse(element);
-      }).toList(),
-      contributors: feedElement.findElements("contributor").map((element) {
-        return AtomPerson.parse(element);
-      }).toList(),
-      categories: feedElement.findElements("category").map((element) {
-        return AtomCategory.parse(element);
-      }).toList(),
-      generator:
-          AtomGenerator.parse(findElementOrNull(feedElement, "generator")),
-      icon: findElementOrNull(feedElement, "icon")?.text,
-      logo: findElementOrNull(feedElement, "logo")?.text,
-      rights: findElementOrNull(feedElement, "rights")?.text,
-      subtitle: findElementOrNull(feedElement, "subtitle")?.text,
+      id: parseUriLiteral(feedElement, "id"),
+      title: parseTextLiteral(feedElement, "title"),
+      updated: parseDateTimeLiteral(feedElement, "updated"),
+      items: feedElement.findElements("entry").map((e) => AtomItem.parse(e)).toList(),
+      links: feedElement.findElements("link").map((e) => AtomLink.parse(e)).toList(),
+      authors: feedElement.findElements("author").map((e) => AtomPerson.parse(e)).toList(),
+      contributors: feedElement.findElements("contributor").map((e) => AtomPerson.parse(e)).toList(),
+      categories: feedElement.findElements("category").map((e) => AtomCategory.parse(e)).toList(),
+      generator: AtomGenerator.parse(findElementOrNull(feedElement, "generator")),
+      icon: parseUriLiteral(feedElement, "icon"),
+      logo: parseUriLiteral(feedElement, "logo"),
+      rights: parseTextLiteral(feedElement, "rights"),
+      subtitle: parseTextLiteral(feedElement, "subtitle"),
     );
   }
+
+  XmlDocument toXml() {
+    var doc = parse('<?xml version="1.0" encoding="UTF-8"?><feed xmlns="http://www.w3.org/2005/Atom"></feed>');
+    var b = XmlBuilder();
+    build(b);
+    var feed = doc.findAllElements('feed').first;
+    b.build().children.forEach((c) => feed.children.add(c.copy()));
+    return doc;
+  }
+
+  void build(XmlBuilder b) {
+    if (id == null) throw Exception('must have an id');
+
+    b.element('id', nest: () => b.text(id));
+    b.element('title', nest: () => title == null ? '' : b.text(title));
+    b.element('updated', nest: () => b.text(updated.toUtc().toIso8601String()));
+
+    if (links != null) links.forEach((l) => l.build(b));
+    if (authors != null) authors.forEach((a) => a.build(b, 'author'));
+    if (contributors != null) contributors.forEach((c) => c.build(b, 'contributor'));
+    if (categories != null) categories.forEach((c) => c.build(b));
+    if (generator != null) generator.build(b);
+
+    if (icon != null) b.element('icon', nest: () => b.text(icon));
+    if (logo != null) b.element('logo', nest: () => b.text(logo));
+    if (subtitle != null) b.element('subtitle', nest: () => b.text(subtitle));
+
+    if (items != null) items.forEach((i) => i.build(b));
+  }
 }

lib/domain/atom_generator.dart

@@ -1,19 +1,32 @@
 import 'package:xml/xml.dart';
 
 class AtomGenerator {
-  final String uri;
+  final Uri uri;
   final String version;
   final String value;
 
-  AtomGenerator(this.uri, this.version, this.value);
+  AtomGenerator({
+    this.uri,
+    this.version,
+    this.value,
+  });
 
   factory AtomGenerator.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
+    if (element == null) return null;
     var uri = element.getAttribute("uri");
-    var version = element.getAttribute("version");
-    var value = element.text;
-    return new AtomGenerator(uri, version, value);
+    return AtomGenerator(
+      uri: uri == null ? null : Uri.parse(uri),
+      version: element.getAttribute("version"),
+      value: element.text,
+    );
+  }
+
+  void build(XmlBuilder b) {
+    //    <generator uri="http://foo.bar.news/generator" version="1.0">Foo bar generator</generator>
+    b.element('generator', nest: () {
+      if (uri != null) b.attribute('uri', uri);
+      if (version != null) b.attribute('version', version);
+      if (value != null) b.text(value);
+    });
   }
 }